flexible fiberoptic laryngoscope guided intubation

Acta Medica Mediterranea, 2015, 31: 913

FLEXIBLE FIBEROPTIC LARYNGOSCOPE GUIDED INTUBATION IN DIFFICULT ORAL INTUBATION: AN AIRWAY MANAGEMENT CHALLENGE IN DENTAL ABSCESS INDUCED TRISMUS

CALOGERO GRILLO1, FRANCESCO SGALAMBRO2, CATERINA GRILLO1, CLAUDIO ANDALORO1, GIUSEPPE FUGALE1, ALESSIO FALLICA1, SALVATORE FERLITO1 1 Department of Medical Surgical Specialties, ENT Clinic, University Hospital “Vittorio Emanuele-Policlinico” Catania 2 Department of Anaesthesia and Intensive Care Oncology Institute of the Mediterranee Viagrande, Catania, Italy

ABSTRACT İntroduction: Odontogenic abscesses with the involvement of facial or cervical spaces can be life-threatening and often have to be drained under general anaesthesia. Trismus and swelling can make intubation with a Macintosh laryngoscope difficult or even impossible. However, several indirect laryngoscopes and procedures are available to facilitate tracheal intubation when conventional direct laryngoscopy has failed but the success and safety of these techniques in patients with a complicated airway management have not yet been established. Methods: We retrospectively compared two different approaches for tracheal intubation in 100 patients with severe cervicofacial dental abscess induced trismus: Nasotracheal intubation with flexible fiberoptic laryngoscope and orotracheal intubation with the aid of a conventional Macintosh laryngoscope. All patients were scheduled for surgical incision and drainage of the abscess under general anaesthesia. Depending on pre-operative airway evaluation, patients were allocated to expected easy or difficult intubation groups, on the basis of mouth opening, modified Mallampati score, history of difficult intubation, obvious swelling or reduced oropharyngeal space. Success rate, visualization of the glottis and intubation duration were evaluated. Results: All the expected easy intubations were successfully performed with the respective technique. In the expected difficult intubation group, the success rate was higher (25 ⁄ 27 vs 6 ⁄ 23; p < 0.01), the view at the glottis was better ( p < 0.01) and intubation duration was shorter ( p < 0.01) with the flexible fiberoptic laryngoscope compared with the Macintosh, respectively. Conclusion: In patients with odontogenic abscesses and difficult tracheal intubations, the use of a flexible fiberoptic laryngoscope is more effective than the Macintosh laryngoscope.

Key words: Difficult intubation, dental abscess, trismus, flexible fiberoptic laryngoscopy. Received November 30, 2014; Accepted May 02, 2015

Introduction Odontogenic abscesses are the most frequent cause of inflammatory conditions in the cervicofacial region, although the widespread availability of antibiotics has reduced their incidence drastically(1-2). They should be suspected in patients presenting with an acute cervicofacial swelling or trismus(3). Trismus is the inability to normally open the mouth. Inflammation of soft tissue around impacted third molar tooth is the most common cause of trismus. Other causes include tetanus, inflammation of muscles of mastication, peritonsillar

abscess, temporomandibular joint disorders, as a temporary side effect of many stimulants of the sympathetic nervous system and some recreational drugs(4). The degree of trismus should be evaluated using a ruler to measure the vertical distance between the upper and lower central incisor teeth (inter-incisor distance). An inter-incisor opening of less than 30 mm correlates with difficulties in endotracheal intubation(5). Odontogenic abscesses are potentially life-threatening diseases, where delayed diagnosis or inadequate treatment can easily lead to further serious complications and even fatal end by developing sepsis, or by the direct

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spread to vital organs or areas, typically into the mediastinal space(6-7) such as Ludwig’s angina and necrotizing mediastinitis (8). However, in the last decades, there is a significant increase in survival rates, but mortality still can reach 11%(9). So a careful assessment and management with an early incision and drainage, mostly under general anaesthesia, of all spaces affected by the abscess is required to prevent or minimize the development of these complications(10). This generally involves an otolaryngologist, a dentist and an anesthetist, this latter necessary for an adequate airway management plan particularly for those cases where tracheal intubation can be complicated by the presence of trismus, intraoral and/or pharyngeal swelling and can be difficult or even impossible when performed with a conventional direct laryngoscopy (11). Several indirect laryngoscopes and procedures are available to facilitate tracheal intubation where conventional direct laryngoscopy failed, but the success and safety of these techniques in patients with cervicofacial abscesses and complicated airway management have not yet been established(12). This study summarizes our experience with two different approaches for tracheal intubation of patients with severe odontogenic abscesses that had spread into the facial or cervical spaces and had caused an interincisor distance of < 30 mm: Nasotracheal intubation with flexible fiberoptic laryngoscope and orotracheal intubation with Macintosh laryngoscope. Material and methods At the ENT Clinic of the Medical-Surgical Specialties Department of the University of Catania, a retrospective study, regarding the period between January 2013 and April 2014 has been carried out. This work has included 100 patients (52 men and 48 women, mean age 39 years, range 26-56) scheduled for surgical incision and drainage of an odontogenic abscess under general anaesthesia. We have enlisted in the study only patients with an abscess of the deep facial or cervical spaces, patients with a superficial abscess that could be drained intra-orally without drainage of the adjacent spaces were excluded. Patients were divided into two groups of 50 patients each, depending on airway evaluation findings at the pre-operative visit. Each of the two

Calogero Grillo, Francesco Sgalambro et Al

groups has been further divided into two subgroups: Macintosh and flexible fiberoptic laryngoscope subgroups according to the technique used for the intubation. All cases where intubation with the conventional Macintosh laryngoscope or flexible fiberoptic laryngoscope failed, despite a maximum of three attempts, they were considered as failed intubations(13). Patients with difficult intubation predictors, such as inter-incisor distance of 30 mm or less, a modified Mallampati score of > 3, documented history of difficult intubation, obvious swelling and/or reduced oropharyngeal space, were included in the expected difficult intubation group. The other patients were included in the expected easy intubation group. Before induction of anaesthesia, the inter-incisor distance during maximal active mouth opening was measured and the modified Mallampati score was assessed with the patient in the sitting position. For the assessment of the Mallampati score, the patients were asked to open their mouths as widely as possible and to protrude their tongues when possible(14). At tracheal intubation, the visualization of the laryngeal inlet was assessed according to the classification of Cormack and Lehane: I, vocal cords visible; II, less than half of the glottis or only the posterior commissure is visible; III, only the epiglottis is visible; IV, none of the foregoing is visible(15). General anaesthesia was induced with propofol, remifentanil administered via target-controlled infusion (TCI) and succinylcholine (1 mg/kg). The duration of the complete intubation attempt was measured as the time from the end of face mask ventilation, until the appearance of the End-tidal CO2 (EtCO2) waveform. In each group, procedures for intubation with a Macintosh laryngoscope or flexible fiberoptic laryngoscope were carried out according to those described by other authors(16-17). When these procedures failed with the Macintosh laryngoscope despite all manoeuvres, the patients were intubated using the flexible fiberoptic laryngoscope. If intubation was not possible with either technique, the patient was awakened and the intubation attempt has been declared failed. Complications due to nasal intubation were noted. During the tracheal intubation, standard monitoring, i.e. non-invasive arterial pressure measurement, heart rate and arterial oxygen saturation (pulse oximeter), was performed and the results were recorded before induction of anaesthesia and at the end of the intubation.

Flexible fiberoptic laryngoscope guided intubation in difficult oral intubation: ...

We considered the intubation time, success rate and laryngeal view of each intubation technique as the primary outcome variables for the expected easy and difficult intubation groups, respectively. Hypotheses were tested using the x2 test (success rate of tracheal intubation, visualization of the glottis according to Cormack and Lehane) and t-test with a Bonferroni correction for multiple testing (intubation duration, vital signs and complications). Differences were considered significant for p < 0.05. Results There was no significant differences regarding the anthropometric data of the patients, both groups and subgroups (Table 1). Easy intubation (n = 50 M/F = 0.92)

Difficult intubation (n = 50 M/F = 1.17)

Macintosh (n=26)

Flexible fiberoptic laryngoscope (n=24)

Macintosh (n=23)

Flexible fiberoptic laryngoscope (n=27)

Age; years

53 [21- 72]

46 [20- 78]

51 [19- 69]

56 [20- 75]

Weight; kg

69 [43- 95]

67 [45- 102]

70 [41- 110]

73 [48- 99]

Mallampati score; 1/2/3/4

11/12/0/0

12/15/0/0

0/0/11/14

0/0/10/15

Interincisor distance; mm

40 [35- 60]

38 [36- 52]

24 [16- 29]

24 [16- 30]

Table 1: Distribution within the two groups and related subgroups with regard to sex, age, weight, Mallampati score and interincisor distance. Values are median [range] or number.

The tracheas of all patients with an expected easy intubation were successfully intubated both with Macintosh technique and with flexible fiberoptic laryngoscope technique, whereas patients belonging to difficult intubation group have reported a success rates in Macintosh and flexible fiberoptic laryngoscope subgroups of, respectively, 26,1% (6/23) and 92,6% (25/27) (p < 0.01). Among the 17 patients in whom intubation failed with the Macintosh laryngoscope, subsequent intubation with the flexible fiberoptic laryngoscope was successful. Of the two patients in whom intubation was not successful with the flexible fiberoptic laryngoscope was performed an elective tracheostomy using local anesthesia. Time for intubation did not differ between the two techniques (p = 0.5, Fig. 1), as well as the view at the glottis according to the classification of Cormack and Lehane (p = 0.11; Fig. 2) in patients with an expected easy intubation.

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Easy intubation

Difficult intubation

Expected intubation conditions

Fig. 1: Time for intubation using Macintosh (white bars) or flexible fiberoptic laryngoscope (black bars) in patients scheduled for tracheal intubation. Intubation time did not differ between the two techniques in expected easy intubation patients group (p = 0.5), instead, it was significantly faster with the flexible fiberoptic laryngoscope for patients with expected difficult intubation (p